1. Field of the Invention
This invention relates in general to position locating and in more particularity to a method and system for accurately locating a specific position.
Although both the method and the system are of general utility they are especially useful in offshore oil surveys where it is important that a specific location be accurately and precisely identified. In an operation such as an offshore oil survey two transmitting stations would be land-based whereas a receiving station would be located on an offshore vessel which can be moved to an exact location which is being sought.
2. Description of the Prior Art
Many phase or time comparison systems have been developed for locating a position and are in use today. There are those based on the radar principle in which an echo or return of signal technique is used; there are those based on the use of transponders where receipt and retransmission of a signal are utilized; and there are those based on the Loran principle where time difference in the receipt of two transmitted pulses define a hyperbolic line of position.